About: CT Sounds HYDRO-8 8" 300W RMS Shallow Mount Subwoofer
CT Sounds is proud to introduce the hydro shallow mount subwoofer series after completing a rigorous R&D process spanning 2 years! Our goal was to engineer a 300-watt 8” shallow-mount subwoofer with a mounting depth below 3.5” that was suitable for both sealed & ported enclosures. To achieve this, we focused on the EBP (Efficiency Bandwidth Product). As a general rule, EBP 100, is used only for ported enclosures. EBP = FS/QES.
Our 1st prototype utilized a 50.8 mm voice coil & 30 oz magnet resulting in a high QES rating of 1.05 and low EBP of 44.1. The 2nd prototype utilized a 44.7 mm voice coil & 30 oz magnet resulting in a slightly lower QES rating of 0.843 and a slightly higher EBP of 54.8. After the 1st and 2nd prototypes, we determined a larger motor assembly was needed to provide a more controlled electrical system (lower QES). This led us to invest in a custom-tooled basket (used in the final prototype) to keep the mounting depth below 3.5”.
The 3rd and final prototype uses a 44.7 mm voice coil & 40 oz magnet resulting in a reduced QES rating of 0.577 and a balanced EBP of 80.07. In testing, we ran into mechanical noise due to the larger motor assembly and voice coil in a confined space. Therefore, we invested in a custom-tooled cone to maximize the excursion capability by creating an equal distance between the cone, spider, and bottom plate. The result is an 8” shallow-mount subwoofer that is extremely responsive in both sealed & ported enclosures.
Product Highlights:
RMS Power: 300 Watts
MAX Power: 600 Watts
Voice Coil Configuration: Dual 2 Ohm (D2) or Dual 4 Ohm (D4)
Use Cases: Sealed & Ported Enclosures
Specifications:
Product Type: Car Subwoofer
Subwoofer Size: 8"
Voice Coil Configuration: Dual 2 Ohm (D2) or Dual 4 Ohm (D4)
RMS Power: 300 Watts
MAX Power: 600 Watts
Voice Coil Type: 1.75 Inch - 4 Layer High-Temperature Copper Voice Coil
Magnet Type: Y35
Bottom Plate Type: Low Carbon Iron
Surround Type: Dual White Stitched Competition Mega Foam Surround
Cone Type: Composite Paper with 3% Carbon Fiber Reinforcement
Tinsel Lead Type: Single Braided Flat Copper Tinsel Leads
Terminal Type: 12 Gauge Push Terminals
Basket Type: Stamped Steel
Spider Material: Poly-Cotton Blend
Thiele & Small Parameters
D2
D4
Electrical Factor (Qes)0.5770.668
Mechanical Factor (Qms)6.5496.083
Total Factor (Qts)0.5310.602
Free Air Resonance (Fs)46.20 Hz47.47 Hz
Equivalent Volume (Vas)10.298 L10.427 L
Mechanical Mass (Mms)82.895 g77.535 g
Mechanical Compliance (Cms)0.143 m/N0.145 m/N
DC Resistance (Re)3.9 Ω6.4 Ω
BL Factor (BL)12.751 Tm14.880 Tm
Cone Area (Sd)227 cm²227 cm²
Excursion (one way) (Xmax)8 mm8 mm
Sensitivity (SPL)84.48 dB84.48 dB
Subwoofer Measurements:
Cutout Diameter: 7.51"
Overall Diameter: 8.77"
Mounting Depth: 3.26"
Box Specifications:
Displacement: 0.02 ft3
Box Recommendations:
Sealed: 0.35 ft3
Ported: 0.875 ft3
Tuning Frequency: 36 Hz
Port Area: 14 in2
*Enclosure recommendations do not account for subwoofer, bracing, and port displacement.
